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On the Energy Efficiency of Dual Clutch Transmissions and Automated Manual Transmissions

Vacca, Fabio, Pinto De, Stefano, Hartavi Karci, Ahu Ece, Gruber, Patrick, Viotto, Fabio, Cavallino, Carlo, Rossi, Jacopo and Sorniotti, Aldo (2017) On the Energy Efficiency of Dual Clutch Transmissions and Automated Manual Transmissions Energies, 10 (10), 1562.

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The main benefits of dual clutch transmissions (DCTs) are: (i) a higher energy efficiency than automatic transmission systems with torque converters; and (ii) the capability to fill the torque gap during gear shifts to allow seamless longitudinal acceleration profiles. Therefore, DCTs are viable alternatives to automated manual transmissions (AMTs). For vehicles equipped with engines that can generate considerable torque, large clutch-slip energy losses occur during power-on gear shifts and, as a result, DCTs need wet clutches for effective heat dissipation. This requirement substantially reduces DCT efficiency because of the churning and ancillary power dissipations associated with the wet clutch pack. To the knowledge of the authors, this study is the first to analyse the detailed power loss contributions of a DCT with wet clutches, and their relative significance along a set of driving cycles. Based on these results, a novel hybridised AMT (HAMT) with a single dry clutch and an electric motor is proposed for the same vehicle. The HAMT architecture combines the high mechanical efficiency typical of AMTs with a single dry clutch, with the torque-fill capability and operational flexibility allowed by the electric motor. The measured efficiency maps of a case study DCT and HAMT are compared. This is then complemented by the analysis of the respective fuel consumption along the driving cycles, which is simulated with an experimentally validated vehicle model. In its internal combustion engine mode, the HAMT reduces fuel consumption by >9% with respect to the DCT.

Item Type: Article
Divisions : Faculty of Engineering and Physical Sciences > Mechanical Engineering Sciences
Authors :
Pinto De,
Hartavi Karci, Ahu
Viotto, Fabio
Cavallino, Carlo
Rossi, Jacopo
Date : 11 October 2017
DOI : 10.3390/en10101562
Copyright Disclaimer : © 2017 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY license(
Uncontrolled Keywords : dual clutch transmissions; hybridised automated manual transmissions; power loss contributions; experiments; driving cycle simulations
Depositing User : Jane Hindle
Date Deposited : 17 Oct 2017 12:21
Last Modified : 16 Jan 2019 18:57

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